There has been an attempt of disposing an intake control valve with good response at the upstream side of an intake valve in an intake passage in an internal combustion engine for supercharging. In such an engine, the intake control valve is controlled to open after opening timing of the intake valve and closed in proximity to closing timing of the intake valve. As a result, air in the intake passage positioned at the upstream side of the intake control valve abruptly flows into a combustion chamber under a negative pressure at a last period of an intake stroke of the engine, and a great deal of the air can be filled inside the combustion chamber due to a kind of an inertia supercharge effect.
This supercharge, which is called pulse charge or impulse charge, is more excellent in control response than a turbo charge system and can eliminate a so-called acceleration delay of a vehicle. The technology relating to such pulse charge is in detail disclosed in “Impulses for Greater Driving Fun” which was press-released on September 9 from Siemens VDO Automotive AG in 2003 Frankfurt Motor Show, for example. [Non-Patent Document 1] “Impulses for Greater Driving Fun” of Pamphlet relating to the issue from Siemens VDO Automotive AG (issue of the ninth of September 9 in 2003).
However, although a large variation in an intake air quantity occurs caused by a minute change in open ing timing of the intake control valve, conventionally this pulse charge is, performed without taking into account a characteristic balance between the cylinders for an engine having a plurality of cylinders.
Therefore, an object of the present invention is to provide a control device which can suppress unbalance in characteristic between a plurality of cylinders in an engine capable of performing pulse charge.